Pouch Battery Lead Tab Breaking Portion Design
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Solution Overview
Problem
Pouch-type secondary batteries face limitations in energy density due to the space required for connecting electrode tabs, lead tabs, and safety measures, which can lead to bulkiness and increased risk of overheating or explosion.
Innovation Solution
The design incorporates a bending connection portion for the lead tabs within the pouch case, featuring a breaking portion with a small cross-sectional area that breaks when an overcurrent is applied or the pouch case expands, minimizing the space occupied by the connection and safety features while ensuring current interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connection methods and safety means are used, then safety is ensured, but the battery becomes bulky and energy density decreases
Solution Approach 1:
The lead tab is integrated with the pouch case cover through injection molding, merging two separate components into one. This eliminates the need for separate connection portions and reduces the overall space required for both the connection structure and safety features, directly resolving the contradiction between safety and compactness.
Solution Approach 2:
The breaking portion (safety feature) is embedded within the lead tab structure itself, which is nested within the pouch case cover. This nested arrangement allows the safety mechanism to occupy minimal space within the existing structure, preventing battery bulkiness while maintaining safety functionality.
2Reliability
If conventional connection methods are used, then connection reliability is ensured, but the space occupied by connection portions increases
Solution Approach 1:
The lead tab connection portion is merged with the pouch case cover through injection molding, creating an integrated structure. This eliminates separate connection components and reduces the connection portion area to the minimum required for functional connection, while maintaining connection reliability through the integrated design.
Solution Approach 2:
The lead tab connection portion is designed with a flexible, thin-profile structure that integrates into the pouch case cover. This flexible design allows for reliable electrical connection while occupying minimal space, directly addressing the contradiction between connection reliability and connection portion area.
3Reliability
If breaking portion is positioned far from electrode tab, then safety function is improved, but space occupation increases
Solution Approach 1:
The breaking portion is nested within the lead tab structure that is itself integrated into the pouch case cover. This nested arrangement positions the safety feature close to the electrode tab connection point without requiring additional space, as the breaking portion utilizes the existing lead tab volume.
Solution Approach 2:
The breaking portion is positioned in a different spatial dimension within the lead tab structure, utilizing the vertical or lateral space within the lead tab rather than extending the overall battery dimensions. This allows the safety function to be effective while minimizing space occupation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances energy density by reducing the space needed for connections and safety features, effectively preventing explosions by interrupting current flow when the pouch case expands.
Implementation Method 1
the breaking portion... being broken when an overcurrent is applied or the pouch case expands
Data Source
AI summary
A pouch type secondary battery may include an electrode assembly, electrode tabs connected to the electrode assembly, a pouch case to accommodate the electrode assembly and the electrode tabs in a sealed state, and lead tabs extending to the outside by passing through the pouch case in a state of being connected to the electrode tabs, wherein the lead tabs include a bending connection portion provided in the pouch case, and a breaking portion provided on a side of the bending connection portion to have a relatively small cross-sectional area and being broken when an overcurrent is applied or the pouch case expands.